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Lacustrine sediments, 13 m thick, have been discovered under a Late Valdaian (Late Weichselian) moraine complex in a palaeokarst depression at Biržai, northern Lithuania. Wood fragments from silty layers in the basal part of the section were 14C dated at 34,440 ± 1500 (Vs-412) and 33,460 ± 1060 BP (LU-1633). Pollen analytical results suggest that taiga landscapes similar to the present-day environments in the Pechora Basin and eastern Urals occurred on the southern cryogenic grounds. Evidently, the ice sheet did not penetrate into the eastern Baltic region during the Middle Valdaian interval.  相似文献   
2.
The Quaternary glacial sequences in the Baltic region in Estonia. Latvia and Lithuania are relatively complete and reasonably well studied. The maximum thickness of deposits (200 300 m) is found in the uplands and ancient valleys. Tills of several genetic types have been described and in this paper the present view on the structure of the Pleistocene cover is given. The ice movement and glacial sedimentation were controlled by climate. underlying topography and tectonic processes.  相似文献   
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